On July 27, 2012, about 1350 central daylight time, a Vans RV-6, N766HS, collided with a Vans RV-4, N122JA, after landing at Miller Field (KVTN), Valentine, Nebraska. The pilot of the RV-4 was seriously injured and succumbed to his injuries on August 17, 2012. The pilot of the RV-6 sustained minor injuries. Both airplanes were substantially damaged. Both airplanes were registered to and operated by their respective pilots under the provisions of 14 Code of Federal Regulations Part 91 as personal flights. Visual meteorological conditions prevailed at the time of the accident, and no flight plans had been filed. The cross-country flights originated from Jackson Municipal Airport (KMJQ), Jackson, Minnesota, about 1000. According to the pilots involved, this was a flight of four airplanes, three Vans RV-4s and a Vans RV-6, that were en route from the 2012 Experimental Aircraft Association AirVenture in Oshkosh, Wisconsin, to their home bases in Washington State. They had landed for fuel at KMJQ and were landing at KVTN for fuel at the time of the accident. According to the accident report submitted by the pilot of the RV-6, the first airplane, N49DB, an RV-4, landed on runway 14 and exited at the end of the runway. The pilot of the RV-6 said he was following the accident RV-4 (N122JA) and made S-turns on final approach for more separation. He said he also moved to the far left side of the runway in order to avoid wake turbulence over the runway threshold from N122JA. As the RV-6 crossed the runway threshold, he saw that N122JA had landed and was on rollout. The RV-6 pilot flared for landing in a 3-point conventional attitude but did not see that N122JA had moved to the left of the centerline. The collision followed. The pilot exited his airplane and went to the aid of the pilot of N122JA. He said when they landed at other airports, all the airplanes would roll out to the end of the runway, then back-taxi to the ramp together. This was what he had expected. The pilot of the fourth airplane, N579MS, an RV-4, saw the RV-6 making S-turns for spacing behind the RV-4. He said N49DB, the lead aircraft, had landed and had rolled to the end of runway 14 and N122JA had landed on the first third of the runway. He said the RV-6 was close behind and lined up to the left of the centerline and was beginning to touch down. N122JA slowed and started turning left at a runway intersection. The RV-6 then struck the left side of the RV-4 and cartwheeled over the top of it, coming to rest close to the RV-4. The pilot of N579MS abandoned his approach, went around, and landed uneventfully. He also went to the aid of the injured pilot. An employee of the airport's fixed base operator, who was in the shop, looked up and saw the RV-4 bounce up in the air. He said the RV-6 had already gone past the RV-4 and was sliding backwards. He said it appeared that the RV-6 had struck the RV-4 behind the pilot's seat with its propeller and landing gear, almost cutting it in half. A Valentine police officer's report noted that he was dispatched to the airport at 1352. When he arrived, the pilot of the RV-6 told him he did not realize the RV-4 had slowed and had turned into his path. The RV-4 was nearly cut in half. Both wings on the RV-6 bore leading edge damage, and the vertical stabilizer was twisted.